Industrial trucks, especially lift trucks, are usually equipped corresponding to their intended use, with self-contained stationary devices for performing highly specific functions e.g., for picking up, and handling and transporting loads. These trucks may be designed with, among other things, lifting, telescoping, retractable, and pivoting forks, as well as combinations thereof. This permanently established intended use of these devices represents a completely unnecessary limitation of the possible uses of such industrial trucks, and it extremely reduces their flexibility in use. In addition, each type of movement requires a separate drive, so that a plurality of different drive means must be present in the vehicle. In the case of combined movement processes, which occur, e.g., in the case of the use of a pivoting and retractable fork of a commissioning truck, this leads to a high prime cost of the vehicle.
Since most types of movements of these devices for storing, removing and transferring materials in warehouses are of a purely translatory nature, with the exception of pivoting or rotation, they usually take place in a chronological sequence one after another, especially if they are to continue to be able to be easily surveyed by the operating personnel, as a result of which even extended adjustment distance must be accepted. The movement processes necessary for, e.g., the positioning of the pivoting and retractable fork, such as the principal lifting movement of the operator's cage, the initial fork lifting movement, translatory lateral pushing of the rotating device with the initial lifting frame, rotation or pivoting and synchronous rotation/pushing of the initial lifting frame with load fork, as well as telescoping of the load fork, illustrate the complexity of functions and the associated adjusting operations of such devices. Even travel movement of the entire industrial truck is sometimes necessary for target control for many applications. The resulting, relatively long cycle times of the devices for picking up, depositing or storing, removing and transferring goods needlessly limit the economy of the industrial trucks. In addition, it is absolutely necessary to stop the entire industrial truck for the duration of repair work in the case of malfunction or failure of one of these permanently installed devices.
Moreover, both static and dynamic attachments, e.g., ram attachments, jib type cranes, hooks, bale, barrel or pincer clamps, clamping forks, etc., with which industrial trucks can be retrofitted depending on needs or use, have been known. However, these usually are almost exclusively the load pickup means themselves, which usually have no drive means of their own, which presupposes that these already have to be present on the industrial truck. These attachments are also used almost exclusively for certain special purposes, and they usually do not permit any complicated movement processes, so that they can be used only with limitations.